Potentiometric determination of lead tetraacetate with sodium oxalate

Lithium interference with potentiometric sodium determination.

Direct potentiometric determination of sodium ion in blood. I. Potentiometric response in simple sodium chloride solutions.

We measured the emf of NaCl solutions (120-160 mmol/L) with a home-built cell in steady-state and with some commercial direct potentiometric analyzers about 20 s after the sample is introduced into the instrument. We compared the results with the theoretical sodium ion activity calculated according to different thermodynamic theories. The slope of the calibration graph was calculated with and w...

Determination of urinary oxalate with commercially available oxalate oxidase.

For this direct colorimetry of urinary oxalate, commercially available oxalate oxidase (EC 1.2.3.4) is used. The urine is first diluted, to diminish the effect of interfering substances. Analytical recovery of oxalate from urines with five different oxalate concentrations (0.4 to 2.0 mmol/L) ranged from 92 to 109% (mean 99%). The within-day and between-day precision (CV) of the method for a wid...

Potentiometric Determination of Coextraction Constants

1 A theoretical treatment of potentiometric data is applied to calculate coextraction 2 constants (K IA) for three potassium salts from water into a liquid nitrobenzene phase. 3 The experiment involves treating nitrobenzene as a membrane and contacting it with 4 two aqueous solutions of different ion activities. In the presence of either a cation or 5 anion exchanger, the ratio of activities of...

Enantioselective aziridination of alkenes with N-aminophthalimide in the presence of lead tetraacetate-mediated chiral ligand.

[reaction: see text] Reaction of various N-enoyl oxazolidinones 5a-f with N-aminophthalimide and lead tetraacetate in the presence of camphor-derived chiral ligands provides the desired N-phthalimidoaziridines 6a-f in good to high enantiomeric excess (67-95% ee) at 0 degrees C within 15 min. The absolute stereochemistry of the corresponding aziridine derivatives was established by chemical corr...